Colorado has ordered Uber to pay a fine of $8.9 million for allowing individuals with disqualifying criminal or motor vehicle offenses, or without valid licenses, to drive for the company, Reuters reports. The company blamed an “error” in its background check process for the bad drivers.

The Colorado Public Utilities Commission (PUC) said its probe found violations that included 12 drivers with felony convictions, 17 drivers with major moving-vehicle violations, and three drivers with a type of driver’s license required only after recent drunk-driving convictions. The commission said that Uber’s background checks also failed to identify a number of aliases used by their drivers, including one driver who was “a convicted felon, habitual offender, and at one point in his past had escaped from the Colorado Department of Corrections.” Nevertheless, after he was released from prison, he became a driver for Uber. The company was cited $2,500 a day for each day a disqualified driver was found to have worked.

“We have determined that Uber had background check information that should have disqualified these drivers under the law, but they were allowed to drive anyway,” Doug Dean, the commission’s director, said in a statement. “PUC staff was able to find felony convictions that the company’s background checks failed to find, demonstrating that the company’s background checks are inadequate. In other cases, we could not confirm criminal background checks were even conducted by Uber.”

In a statement, Uber says it recently discovered a “process error that was inconsistent with Colorado’s ride-sharing regulations and proactively notified the Colorado Public Utilities Commission (CPUC). This error affected a small number of drivers and we immediately took corrective action. Per Uber safety policies and Colorado state regulations, drivers with access to the Uber app must undergo a nationally accredited third-party background screening. We will continue to work closely with the CPUC to enable access to safe, reliable transportation options for all Coloradans.” Asked if the company planned on paying the fine, a spokesperson said they were “evaluating our options.”

This isn’t the first time Uber has been reprimanded for its security policies. In 2014, the cities of Los Angeles and San Francisco sued the ride-hailing company for claiming its background checks were the most thorough in the industry, despite the fact that Uber does not take drivers' fingerprints like many taxi companies do. Uber paid $10 million to settle the suit. A new lawsuit seeking class action status was filed recently by two anonymous women who claim to have been raped or assaulted by Uber drivers. Their lawsuit is seeking to force Uber to implement stricter background check policies.

Fingerprinting drivers is a common point of contention between Uber and local governments. The company left out of Austin, Texas, after city officials there passed a law requiring finger printing for drivers. (Uber has since returned after a state law was passed voiding the requirement.)

In response to the Colorado decision, Uber notes that the state’s laws governing app-based ride-hailing services are uniquely strict. According to current Colorado law, a driver convicted of a felony for nonviolent crimes, such as trespassing or forgery, in their lifetime would not be eligible to drive for Uber in Colorado.